Manufacture of headlights



May 8, 1928.

w. H. woon MANUFAC'LURE OF HEADLIGHTS 2 Sheets-Sheet 1 WILLIAM H. WOODFiled Aug. 17, 1923 I l I I l a l l I INVE NTOK WW ATTORNEYS on w W. H.WOOD MANUFACTURE OF HBADLIGHTS May 8, 1928.

Filed Aug. 17. 1923 2 Sheets-Sheet 9 fi 5j6 5 97 WlLLlAM H. W000 IINVENTOR.

v ATTORNEYS Patented May 8, 1928.

UNITED STATES WILLIAM 1:. W001), or SOUTH EUCLID,OH10.

munacronn or nnanmenrs.

Application filed August 17, 1928. Serial N0. 657,996.

This invention relates to vehicle headlightsand has for its object theprovision of a new and improved punch and die whereby a onepiece sheetmetal reflector canbe simply and easily made which shall produce alegally acceptable and practically satisfactory distribution of lightwithout the use of lenses, prisms, shades, dimmers or other expensive,fragile, or light killing devices. Other objects of the invention relateto the production of such a punch and die each from a single piece ofmetal; the provision of a punch of such construction that it can readilybe dressed or re-shaped; the provision of a device of this characterwhich can be very quickly and cheaply produced; the provision of animproved headlight reflector, while further objects and advantages ofthe invention will become apparent as the description proceeds.

In my former application filed Jan. 24, 1923, Serial No. 614,694 Idescribed a certain mathematical surface for use in the construction ofheadlight reflectors for producing a light which is not only legallysatisfactory, but also to a considerable extent in:

dependentof minor variations in focal distance. The present inventioncontemplates the use of these curves, or other curves similarly found,but refers specifically to the manner of impressing these curves uponthe metal block whereby the tool itself is produced. In the drawingsaccompanying and forming a part of this application wherein I haveshownin detail one mode of producing my improved tool; Fig. 1 is adiagrammatic view showing the mode of generating my improved curve asemployed for the top portion of my reflector; Fig. 2 shows the modeofgeuerating my improved curve as employed for the lower part of myreflector; Fig. 3 is a diagrammatic View showing the preferredmode ofassembling these curves together and disposing them with reference tothe horizontal, this diagram conforming substantially to the centralvertical sectionof my preferred reflector; Fig. 4 illustrates the firststep in the preparation of my im-' punch shown in Fig. 9; Fig. 11 showsthe same punch after having had the next cut taken off its upperportion; Fig. 12 is a front view of the punch shown in Fig. 11; alsoillustrating the nature of the next succeedingstep; Fig. 13 is a sideelevation of the 'con'ipleted punch; Fig. 14 is a vertical centralsection of a reflectormade thereon;

Fig. 15, is a front elevation of the reflector shown in Fig. 14; Fig. 15is a face View of the die or ring member. with which the punchco-operates; and Fig. 17 is a sectional View of the ring shown in Fig.16.

My improved curve consists in effect of a plurality of parabolas mergingone into the other, each portion corresponding to a different focalpoint. The shape of the curve for the top half of the reflector ismaterially different from that of the lower part and is developed asfollows: I draw the line 1--1 of Fig. l torepresent the horizontal axisand above it I locate the point S say onefourth inch there-from, thisdistance corresponding to the intended elevation ofthe light sourceabove the reflector axis. It will be understood that this displacementmay be either less or greater than the amount I have suggested, and willalso depend upon the focal depth of the curve. difficulty will beexperienced in merging together the different surfaces inasmuch astheyywill be severely warped; if made too small, the desiredlightcontrol will not be obtained. The present drawings are exaggeratedin all respects in; order to'show the theory of operation within thesmall scale permitted.

Through the point S I draw a vertical line two inches long ending at theaxis at This line corresponds to the parameter of a parabola anditsupper end 3 is a point of the curve at which its inclination to the axis1-1 is substantially 45. Also at a point in the rear of the line 2-3 Idraw a parallel line. I)--I) at the same distance from the point 3 as 3is distant from This line corresponds to the directrix of a parabola,and the procedure thus far conforms exactly to that which would befollowed if a parabola "were to be drawn about the point 2, with a focaldistance of one inch. Of course I do not limit myself to this size.

However, if the point S be considered as a light source, then itsvirtual position along the axis 1 will depend upon the angularity withwhich the rays strike that axis. For

If made too great,

example I now draw an inclinedlilre through the point S so as tointersect both the axis 11 and the probable curve, say the line eintersecting the axis at 4. I then draw a perpendicular E,E the samedistance behind the line D,-D that 4 lies in front of 2 and on theline eI locate the point 5 which is equidistant from the line E-E and theintersection 4. In, other words the point 5 constitutes a pointona-parabola whose true focus is '4 and directrix is E -E. I

I then draw anotl-ier inclined line/g through the-point S "intersectingthe axis at 6, andalso'drawa corresponding directrix (,l-(ias farbehind'DD as the point (ilies in front of the point 2. On this line Ithen ...1'i11(l the point 7 which equidistant from the paint 6 and fromthe line ,GG,, the point being upon aparabola whose focus is (i andwhose directrix is G G.- I repeat the same performance for a sufficient.number of other lines to locate other-points '8, 9, etcand thus plat anaccurate curve between the parameter and-the ,vertex.

I then draw an inclined line through the point S' intersecting the ax1sat 12*between the parameter and the vertex and vto accompany itI draw aperpendicular J-J as far in front of the line D-D as 12 is behind 2,.

after which I find the point 13 on this line which is equidistant fromthe point 12 and the line J-J,- this point-being located on a parabolawhose focus is 12 andwhose directrix is JJ This is repeated forthe lines7c and I--K etc. and giving points 14, 15 andas many other times asdesired after which a curve Y is drawn connecting the points 3, 5, 7, 9,11,13, 15.

To plat the line below the axis I draw a second straight line 2020 as inFig. 2 and place a t one-fourth inch above 1t (or whatever distance Iprev ously employed), a point S from which I- drop a perpendicular 7?intersecting the axis at 21; and on this line at about two andone-fourth mches (more or less, but preferably a little more than thedistance 23 for a reason to be explained hereafter) below the line Ilocate the point 22 which is a point on the curve. Also I drop theperpendicular PP so located that the point 22 shall be equidistantfrom-21 and from PP.

I then draw an inclined line 1 through the point S" intersecting theaxis 20 at 23 behind the point 21and I also draw a second perpendicularQ-Q the same distance in front of YPI as 23 is behind 21. line 1 I thenlocate thepoint 24 equidistant from the point 23 and from the line Afterrepeating this with other lines 1, it,

etc. I find the points 26, 28 etc. sufficient in number to define anaccurate curve. I draw other lines as u, and o intersecting the axis infront of the point 21v and for each I draw a corresponding perpendicularas On the i UU, V-V an equal distance behind the line PP thus findingthe oints 30, 32, etc.

in the same fashion. I t en connect the points 22, 24, 26, 28, '30, 32produclng the curve Z.

It can be dei'i'ionstrated that each of the curves plotted ashereinbefore described concentral vertical section made by assemblingthese curves as shown in Fig. 3, the line 15-91, being superposed uponthe line 20-20 with the point S located slightly behind the point k Ifthe distance 21, 22 was properly chosen relative to the distance2-tl,"the

vertices of the two curves will match properly with the desiredlongitudinal separation of these points which is preferably rather smallsay inch (it will be understood that the present patent drawings areentirely out of proportion in order to produce slifli-, cient separationofthe different points and lines for ready reference). If a light sourceA be located at any point between S and S,

.all rays fallingon Y will be reflected forwardly and downwardly asshown at C. Indeed this downward deflection is sogreat as torender itdesirable to tip the reflector upwardly as regards the horizontal lineI'I"II. The dotted line F in Fig. 3 indicates a true parabola drawnabout the axis 20 for purposes of comparison. 5 I i I will now describethe mode whereby I apply my improved curvesto the Inetaltool wherebythis reflector is made. I first take a suitable block of metal shownbythe dotted outline40 in Fig. 4 and on the one side I turn acylindrical boss 41 while the opposite portionof theblock is formed by asurface of revolution of the portion Z of the curve already described,the axis 2020being coaxial with the boss 41 and with the axis ofrevolution. This produces a mushroom-shaped metal block which. is nowshifted bodily laterally to a new' axis of revolution 42-42 parallel tobut spaced from the axis 20 -20. and the block is again machined toconform to the surface of revolution of the same curve about the axis 42with a radius equal to slightly less than the sum of the displacement 42plus the, previous radius. Vhile in this position I cut into the blockat one side-throughout the are indicated approximately at 4343 in Fig.6, thereby slightly flattening the block on one side and taking off acomparatively thin layer indicatedat the bottom Of Figs. 5 and 6. Thisaccomplished I shift the block still further till -extend over in thesame direction and again turn itabout the axis 45, parallel to the firstaxis but displaced yet further in the same direc tion, and cause thesame to conform throughout a yet narrower area to the surface ofrevolution of the same curve about a radius similarly increased. In thisway I remove a yet narrower region represented by the are 46-46 in Fig.8. A still greater number of settings can be made if desired, but isunnecessary. Indeed I have had excellent results with only a singleoii'set cutting. 3 l

I; now offset the block in the opposite direction to an axis 418 -l8 andmachine it to conform to the surface of revolution of the curve Y aboutthis new axis, the radius of rotation being increased by the distancebe-- tween 20 and 4-8. If this displacement is properly chosen, theblock will be surfaced over only a part of its circun'iference, thebottom portion of the block swinging inside this new surface ofrevolution. In the embodiment here illustrated the curve Y is muchsmaller than the curve Z owing to the comparatively great verticaldisplacement of the points S, S, and for this reason the cut extendsmore than a half circnn'iference, from 49- 44). In actual practice withthe measurements here indicated the cut will not even asemi-cireumference. Either condition is equally satisfactory since theside wings hereafter desribed will lill the gap if such exists.Thereupon the block is again shifted to an axis 50 yet further displacedand is again machined to the same surface of revolution about asimilarly in.- creased radius, only a comparatively narrow strip beingout along the extreme top of the punch as indicated bythe arc 51-51 inFig. 12.

The block is now shifted to a new and very eccentric axis 52, locatedsomewhat be low the axis 20 and very materially to one side, and a sidewing turned throughout the are 53 53 extending from the largest portionof the die to a point substantially opposite the parameter. This wingwill appear slightly flattened and somewhat wedgeshaped as indicatedat Xin Fig. 13; after which the block is again shifted to the axis 5%symmetrically located as regards the axis 59 and corresponding to theare 55 All these various sections, if the work has been carefully doneas herein directed, will merge together with very little unevenness. itwill be necessary to smooth down the meeting edges with a fine file butthe only care necessary in this regard is not to dress the same toomuch, merely to remove rough-- ness and produce a smooth blending. Theblock is now mounted in a base plate 56 shown in Fig. 13 having a shank57 adapted to fit the socket of the punch press plunger, the face andback of this base plate being inclined the amount by which the axis ofthe lamp is todi'verge from horizontal. The punch is ren'iovably securedto this plate so as to permit redressing in case of need.

Owing to this inclination the punch will strike the die at a slightlydifferent angle from that originally exhibited namely along the line(5()-60. This die, therefore, consists merely of a steel ring 61 having.its inner face (52 shaped to conform to the section of the punch alongthis line, Common boiler plate is amply smlicient for this ring. Theabsence of any reentrant angles or deprcssions in the surface of thepunch dispenses with the need for a receiving memher which shall .inother words a bottoming die. The reflector produced by this tool isillustrated in Figs. 14 and 15, and is made by a single stroke of thetool, the edges of the plate being meanwhile gripped against the ring 61in the manor well known to all those skilled in the art of metaldrawing; A por tion of this metal left as at 65 to form a stiffening rimor flange whose exterior is trimmed to circular shape, While the heel ofthe reflector is provided with an aperture V for the reception of thelamp socket, thesame being located sufficiently above the axis 2U-20 tobring the light source. the desired distance therefrom.

It will be understood that I do not limit myself to any one relation ofdistances or ratio between the upper and lower curves or displacement ofthe foci of said curves or in anywise except as herein claimed. Indeedit will be noted that if these directions be accurately followed theaxes 1--1 and 202O will"overlap each other by a short distance. This isno practical detriinei'it but can be avoided by producing the ori alblank about an axis located son'n-iwhere between the lines 20-90 and 42in Fig. The effect of this to cause the line 2%)20 to describe a.cylinder of revolution whose diai'neter is equal to the sum of the cutswhich are to be taken off the top and bottom of the blank. If this bedone at the start, then the final punch will exhibit the exit sectionshown in Fig. 8; if it be not done the device will be narrowed by thisamount, although if properly designed the lightwill still be acceptable.This is only a working allowance such as any carpenter must provideevery time he saws a board, but my invention is not restricted to suchnicetics although the accuracy of the result is improved thereby. Also Ihave described a. device made by swinging the blank about mimei'ous axes20. 42. 48, 5U, :32. Fiat. all of which are parallel to each other whichis extremely convenient in practice since it permits the tool to he madeon a common lathe merely by shifting the block about on the face plate,but I do not limit myself to this coaforin closclv therewith,

parallel arrangement. Also I do not limit myself to the use of all. thecurves and set tings shown, as in some instances it may be feasible todispense with the side wings or other elements; and conversely I may useadditional curves and additional settings.

Certain of the reflectors described herein, and illustrated in thedrawings are claimed in my copendii'ig application filed kieptenr ber22, 1927, Serial No. 221,153, filed as a continuation of my applicationNo. 6l l,694l, filed January 24L, 1923. l

Having thus described my invention What I claim is:

.1. A one-piece metal punch for reflectors having its surface convex atall points and having its different regions formed as surfaces ofrevolution about a plurality of different longitudinal axes.

2. A one-piece metal punch for reflectors having its surface convex atall points and having its different regions formed as sur- 7 faces ofrevolution about a plurality of longitudinal axes, all of which arelocated in a single plane.

3; A one-piece metal .punch for reflectors opposed regions of whichconsist of surfaces of revolution about different longitudi nalaxes ofcurves which are parabolic as regards a focal point displaced from allsuch axes.

4. A one-piece metal punch for reflectors, having the portions uponopposite sides of its principal axis formed as surfaces of revolution ofdissimilar curves about eccentric axes. i

5. A metal punch for reflectors having a portion corresponding to asurface defined by the rotation of a segment of a parabola about an axisinclined to the parabolic axis.

6. A metal punch for reflectors having a portion defined as the surfaceof revolution of a segment of a parabola about an axis which is obliqueto the parabolic axis and displaced from the focal point.

7. A bilaterally symmetrical one-piece metal punch for reflectors Whoseintermediate regions are'surfaces of revolutions of hyperbolas aboutdifferent longitudinal axes.

8. A bilaterally symmetrical metal punch for reflectors having its crosssection defined by a pair of opposed semiovals of unequal curvature, theends of said semiovals being joined, by arcs whose centers lie at thesame side of the longitudinal axis of the oval and upon opposite sidesof the transverse axis.

9. A bilaterally symmetrical metal punch for reflectors whose-lateralregions are surface of revolution about a pair of spaced axes and whoseintermediate regions are surfaces of revolution about a plurality ofparallel axes all of which are contained 1n a plane perpendicular to theplane which contains the first two axes.

10. A bilaterally symmetrical one-piece.

axesall of which are contained in a single.

plane and having its lateral portions connected by surfaces ofrevolution about axes displaced upon. opposite sides of such plane; 11.A one-piece metal punch for automobile headlight reflectors havingexternal portions formed as surfaces of revolution about axes which areoblique to the axis of the punch.

' 12. A one-piece metal punchfor automo bile reflectors, the punch axisoblique to the axis of the curve which defines the reflector surface.

In testimony whereof, l hereun'to afiix my signature. I

l/VILLIAM H. WOOD.

